In the related art, for example, as disclosed in Patent Document 1, a discharge container including a container main body having an inner container in which contents are accommodated and abundant flexibility to be deformed according to reduction in an accommodation amount of the contents and an outer container in which the inner container is installed and configured to be elastically deformed, and a discharge cap mounted on a port section of the container main body and having a discharge port configured to discharge the contents is known. In the discharge container, a suction hole through which external air is suctioned is formed at a position at substantially a center of upper, lower, left and right sides of a trunk section of the outer container and disposed between the outer container and the inner container. In addition, the discharge cap includes a communication hole configured to bring the discharge port in communication with the inside of the inner container, and a valve member configured to switch between allowing and blocking communication between the discharge port and the communication hole.
In the discharge container, when the contents accommodated in the inner container of the container main body are discharged, the outer container of the container main body is squeezed and deformed (elastically deformed). Accordingly, the inner container is deformed with the outer container to be reduced in volume. Then, the pressure of the inner container increases due to the volume-reducing deformation. The valve member is opened by the increased pressure, and the discharge port comes in communication with the inside of the inner container via the communication hole. Accordingly, the contents accommodated in the inner container are discharged from the discharge port.
In addition, a synthetic resin bottle capable of volume-reducing deformation and recovering deformation is known as a discharge container in which viscous contents such as shampoo, sauce, or the like, are dischargeably accommodated. As such a synthetic resin bottle, a so-called delamination bottle-type discharge container in which the inner container is separated from the outer container and the volume thereof is reduced is known. The delamination bottle-type discharge container has a discharge valve configured to form the discharge port of the contents, and a suction valve configured to introduce external air into a space between the outer container and the inner container.
The discharge valve forms the discharge port of the contents. In general, it is not easy to completely empty viscous contents. For this reason, like the related art disclosed in Patent Document 2, a configuration in which a slit valve formed of a soft elastic material is used as a discharge valve and good “liquid exhaustion” can be obtained is considered. In the configuration in which the slit valve is used as the discharge valve, even when the contents are viscous, an action by which they are completely emptied can be accomplished.